Ice and snow on aircraft represent a significant safety issue in aviation and cause, for example, an increase in the weight of the aircraft, sometimes a deterioration of the aerodynamics, and in particular asymmetry in terms of the shape and mass. Not only does this increase the fuel consumption, but the maneuverability of the aircraft can also be significantly impaired, and this can result in serious accidents.
De-icing measures are therefore taken in order both to prevent freezing and to eliminate freezing that has already occurred. In this case, a distinction must be made between ground-based de-icing and in-flight de-icing. Ground-based de-icing takes place immediately before an aircraft takes off, and is usually carried out by spraying glycol mixtures onto relevant surfaces of the aircraft that are at risk of icing up. In-flight de-icing, in contrast, is carried out during a flight and generally takes place from an inside region of the aircraft. According to the conventional procedure, in this case hot bleed air is usually conveyed from the engine compressors into suitable cavities or channels in order to heat adjacent regions and thus to prevent ice formation or to thaw ice that has already formed.
This “thermal” method that is based on bleed air is complex in terms of both the method and the apparatus It requires a high number of components (such as shut-off valves, pipes and branches, suction connection pieces and pressure controllers), and a system of this kind involves complex control, high weight and a large space requirement. In addition, fiber composite structures for example, in particular structures that comprise a binder resin in addition to carbon fibers, cannot be treated using bleed air from the engine compressor. This is because the air to be conveyed out of the engine compressor is generally at a temperature of over 200° C., which would damage the resin-based material in a region in contact with the hot air.
In addition to thermal method, electrical de-icing is also known. For this purpose, thin heating wires or a heating film is/are usually introduced into or applied to the material, and the heating wires or the heating film is/are connected to an electrical power system. Electric heat is thus generated, which heat prevents ice formation and/or melts existing ice. However, the efficiency of this procedure is poor, meaning that a large amount of energy is required. As a result, it is usually used only for viewing windows, in particular windscreens on the cockpit.